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Lowest latency Video capturing, frame grabber, USB, Firewire, IP?

Hello people,

maybe you are a little boring to talk about cameras, but i would need some suggestions.

i´ve always used firewire or usb cameras (mainly because i´ve used only laptops for the performances) and i´ve noticed that there is an appreciable latency in the video signal even using a simple tracking chain (2 or 3 render passes), this is not really important in the most of the situations, but in others it kills the illusion in a performance.

Making some research i´ve found some information explaining that the lowest latency way to capture live video, is using an analog camera and a frame grabber, it has bigger resolution (PAL) and also the analog video cables are cheaper (& longer) than firewire or usb ones.

There is also a very useful documentation about tracking here (thanks! wirmachenbunt, and Frank):
node10.workshop.videotracking

Could someone confirm it? or tell me the best setup to work with very, very low latency?

I´m thinking to buy the Falcon PCI card and a used Hitachi industrial monochrome EIA camera for my setup (i hope enough NIR sensitive, i didn´t find any info about the spectral response), instead of firewire solution, mostly after the nightmare with the Imaging Source drivers.

Anyone with experience with this capture card and vvvv? i saw that there is a wdm driver.
i read also that EyeCon (Frieder Weiss) is developed mostly for this card with some “special” drivers, i think for better response, lower latency ¿?.
btw, is there any difference in latency/performance between the PCI and PCIe model?

The camera works at 60fps interlaced mode, i think with a deinterlace freeframe plugin would be enough to be used for computer vision, isn´t it?

Maybe these questions are obvious, but i´m a post analog video guy ;)

Sorry for the questionnaire, thanks in advance.

Ari.

I can’t say confidently that it provides the lowest latency but my experience with an analogue cctv feed has left me quite impressed. I’ve capture both with a PCI card and a USB2.0 dongle and they both seem to provide they same level of performance (25fps PAL 720x540 or something, and the card /dongle handles to deinterlacing if I remember correctly)

The feed passes through videtextureVideo -> BackgroundSubtraction -> Blur -> and resize(downscaling) before -> AsVideo and Contour, yet theres only a latency of a frame, perhaps two.

That said, a 1/25 is longer than a 1/60 of a second.

Be worth checking with other hardware of course but how critical is the timing of the reaction?

Tracking.zip (655.4 kB)

i’ve been testing with a flea3
it actually reports the latency of each frame in microseconds
a high reading is about 1000+, low readings are 10-100 micro seconds

i think that’d beat whatever you’re getting with analogue equipment
it uses a usb3 interface and has 2048*1552px resolution

and works great with VVVV.Nodes.FlyCapture + VVVV.Nodes.OpenCV :)

p.s. everything you’re doing (videotexture,bgsub,blur,resize) all happens in one thread
which means you can trust that the latency is exactly 1 frame or less (of your mainloop)

i worked with Frieder once: Falcon board with SONY XC-EI50. we had 50-70 meters cable to his Calypso shuttles and there was remarkable latency of few frames.

i’d not recommend analog/interlaced capturing. there is no freeframe to deinterlace…and we have arrived in the digital age.

definitely go for a usb3 or firewire-cam. they give you progressive images and i bet it does not get faster than digital. don’t know about imagingsource drivers, but i can personally recommend ids-imaging cams. their dshow drivers work and there is an api too for direct access.

with the pointgray ones the api seems ok as elliot reported, but beware that their dshow drivers seem crap (from what you read in the forum).

Wow,
thanks a lot for the feedback!, it seems that i´ll keep myself in the digital age.
Maybe i was a little worry about latency since someone said me “it´s nice but there is a little latency, isn´t it?”

I take note of everything, very appreciated.

Ari.

I have to chime in about the PlayStation 3 Eye. Dirt cheap, easy to modify for IR, and does 60fps at 640x480 and -> 75 <- fps at 320x240 with very low latency. You can also get a full spectrum of lenses for it very cheaply once it’s been modded. And there’s a vvvv plugin to handle using two at once.

Thanks mediadog,
i have a modified one to test the patches and i have similar latency than the firewire one, nice device btw.

Ari.

To my knowledge, SDI Capture is the fastest, if you can use a camera that supports SDI output.

Thanks Eno,
i´ll think about it if i have enough money.